1. Field of the Invention
The present invention relates to an antitheft system and a method thereof, which are preferably applicable to an antitheft system used for, e.g., a two-wheeled motor vehicle.
2. Description of the Related Art
Heretofore, as an antitheft system used for a two-wheeled motor vehicle, a vehicle antitheft system has been known in which the system is provided with an acceleration detecting means for detecting accelerations in a plurality of directions of a two-wheeled motor vehicle and a determination means for determining the presence and absence of abnormality associated with the theft of a vehicle based on the accelerations detected by the acceleration detecting means, as disclosed in e.g., a publication of Japanese patent No. 3622723. This vehicle antitheft system is capable of detecting a plurality of conditions of the two-wheeled motor vehicle based on an output from one acceleration detecting means to provide a high antitheft function while realizing the downsizing of the whole system as well as the reduction of cost.
According to the vehicle antitheft system thus structured, however, there has been a problem that it is not able to be easily installed, because, in order to ensure a sufficient detecting capability required for determining the presence of a theft, the system needs to be installed so that two axial directions of the acceleration detecting means may be precisely consistent with two axial directions indicating the front-to-back and the right-to-left directions of the two-wheeled motor vehicle, in the case of employing an acceleration detecting means for detecting accelerations in orthogonal two-axial directions, for example.